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root/net/ipv4/devinet.c

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DEFINITIONS

This source file includes following definitions.
  1. devinet_sysctl_register
  2. devinet_sysctl_unregister
  3. inet_alloc_ifa
  4. inet_rcu_free_ifa
  5. inet_free_ifa
  6. in_dev_finish_destroy
  7. inetdev_init
  8. in_dev_rcu_put
  9. inetdev_destroy
  10. inet_addr_onlink
  11. __inet_del_ifa
  12. inet_del_ifa
  13. __inet_insert_ifa
  14. inet_insert_ifa
  15. inet_set_ifa
  16. inetdev_by_index
  17. inet_ifa_byprefix
  18. inet_rtm_deladdr
  19. rtm_to_ifaddr
  20. inet_rtm_newaddr
  21. inet_abc_len
  22. devinet_ioctl
  23. inet_gifconf
  24. inet_select_addr
  25. confirm_addr_indev
  26. inet_confirm_addr
  27. register_inetaddr_notifier
  28. unregister_inetaddr_notifier
  29. inetdev_changename
  30. inetdev_valid_mtu
  31. inetdev_event
  32. inet_nlmsg_size
  33. inet_fill_ifaddr
  34. inet_dump_ifaddr
  35. rtmsg_ifa
  36. devinet_copy_dflt_conf
  37. inet_forward_change
  38. devinet_conf_proc
  39. devinet_conf_sysctl
  40. devinet_sysctl_forward
  41. ipv4_doint_and_flush
  42. ipv4_doint_and_flush_strategy
  43. __devinet_sysctl_register
  44. __devinet_sysctl_unregister
  45. devinet_sysctl_register
  46. devinet_sysctl_unregister
  47. devinet_init_net
  48. devinet_exit_net
  49. devinet_init

/*
 *      NET3    IP device support routines.
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 *      Derived from the IP parts of dev.c 1.0.19
 *              Authors:        Ross Biro
 *                              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *                              Mark Evans, <evansmp@uhura.aston.ac.uk>
 *
 *      Additional Authors:
 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *      Changes:
 *              Alexey Kuznetsov:       pa_* fields are replaced with ifaddr
 *                                      lists.
 *              Cyrus Durgin:           updated for kmod
 *              Matthias Andree:        in devinet_ioctl, compare label and
 *                                      address (4.4BSD alias style support),
 *                                      fall back to comparing just the label
 *                                      if no match found.
 */


#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <linux/kmod.h>

#include <net/arp.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/ip_fib.h>
#include <net/rtnetlink.h>
#include <net/net_namespace.h>

static struct ipv4_devconf ipv4_devconf = {
        .data = {
                [NET_IPV4_CONF_ACCEPT_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SEND_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SECURE_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SHARED_MEDIA - 1] = 1,
        },
};

static struct ipv4_devconf ipv4_devconf_dflt = {
        .data = {
                [NET_IPV4_CONF_ACCEPT_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SEND_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SECURE_REDIRECTS - 1] = 1,
                [NET_IPV4_CONF_SHARED_MEDIA - 1] = 1,
                [NET_IPV4_CONF_ACCEPT_SOURCE_ROUTE - 1] = 1,
        },
};

#define IPV4_DEVCONF_DFLT(net, attr) \
        IPV4_DEVCONF((*net->ipv4.devconf_dflt), attr)

static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
        [IFA_LOCAL]             = { .type = NLA_U32 },
        [IFA_ADDRESS]           = { .type = NLA_U32 },
        [IFA_BROADCAST]         = { .type = NLA_U32 },
        [IFA_LABEL]             = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
};

static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);

static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                         int destroy);
#ifdef CONFIG_SYSCTL
static void devinet_sysctl_register(struct in_device *idev);
static void devinet_sysctl_unregister(struct in_device *idev);
#else
static inline void devinet_sysctl_register(struct in_device *idev)
{
}
static inline void devinet_sysctl_unregister(struct in_device *idev)
{
}
#endif

/* Locks all the inet devices. */

static struct in_ifaddr *inet_alloc_ifa(void)
{
        struct in_ifaddr *ifa = kzalloc(sizeof(*ifa), GFP_KERNEL);

        if (ifa) {
                INIT_RCU_HEAD(&ifa->rcu_head);
        }

        return ifa;
}

static void inet_rcu_free_ifa(struct rcu_head *head)
{
        struct in_ifaddr *ifa = container_of(head, struct in_ifaddr, rcu_head);
        if (ifa->ifa_dev)
                in_dev_put(ifa->ifa_dev);
        kfree(ifa);
}

static inline void inet_free_ifa(struct in_ifaddr *ifa)
{
        call_rcu(&ifa->rcu_head, inet_rcu_free_ifa);
}

void in_dev_finish_destroy(struct in_device *idev)
{
        struct net_device *dev = idev->dev;

        WARN_ON(idev->ifa_list);
        WARN_ON(idev->mc_list);
#ifdef NET_REFCNT_DEBUG
        printk(KERN_DEBUG "in_dev_finish_destroy: %p=%s\n",
               idev, dev ? dev->name : "NIL");
#endif
        dev_put(dev);
        if (!idev->dead)
                printk("Freeing alive in_device %p\n", idev);
        else {
                kfree(idev);
        }
}

static struct in_device *inetdev_init(struct net_device *dev)
{
        struct in_device *in_dev;

        ASSERT_RTNL();

        in_dev = kzalloc(sizeof(*in_dev), GFP_KERNEL);
        if (!in_dev)
                goto out;
        INIT_RCU_HEAD(&in_dev->rcu_head);
        memcpy(&in_dev->cnf, dev_net(dev)->ipv4.devconf_dflt,
                        sizeof(in_dev->cnf));
        in_dev->cnf.sysctl = NULL;
        in_dev->dev = dev;
        if ((in_dev->arp_parms = neigh_parms_alloc(dev, &arp_tbl)) == NULL)
                goto out_kfree;
        if (IPV4_DEVCONF(in_dev->cnf, FORWARDING))
                dev_disable_lro(dev);
        /* Reference in_dev->dev */
        dev_hold(dev);
        /* Account for reference dev->ip_ptr (below) */
        in_dev_hold(in_dev);

        devinet_sysctl_register(in_dev);
        ip_mc_init_dev(in_dev);
        if (dev->flags & IFF_UP)
                ip_mc_up(in_dev);

        /* we can receive as soon as ip_ptr is set -- do this last */
        rcu_assign_pointer(dev->ip_ptr, in_dev);
out:
        return in_dev;
out_kfree:
        kfree(in_dev);
        in_dev = NULL;
        goto out;
}

static void in_dev_rcu_put(struct rcu_head *head)
{
        struct in_device *idev = container_of(head, struct in_device, rcu_head);
        in_dev_put(idev);
}

static void inetdev_destroy(struct in_device *in_dev)
{
        struct in_ifaddr *ifa;
        struct net_device *dev;

        ASSERT_RTNL();

        dev = in_dev->dev;

        in_dev->dead = 1;

        ip_mc_destroy_dev(in_dev);

        while ((ifa = in_dev->ifa_list) != NULL) {
                inet_del_ifa(in_dev, &in_dev->ifa_list, 0);
                inet_free_ifa(ifa);
        }

        dev->ip_ptr = NULL;

        devinet_sysctl_unregister(in_dev);
        neigh_parms_release(&arp_tbl, in_dev->arp_parms);
        arp_ifdown(dev);

        call_rcu(&in_dev->rcu_head, in_dev_rcu_put);
}

int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b)
{
        rcu_read_lock();
        for_primary_ifa(in_dev) {
                if (inet_ifa_match(a, ifa)) {
                        if (!b || inet_ifa_match(b, ifa)) {
                                rcu_read_unlock();
                                return 1;
                        }
                }
        } endfor_ifa(in_dev);
        rcu_read_unlock();
        return 0;
}

static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                         int destroy, struct nlmsghdr *nlh, u32 pid)
{
        struct in_ifaddr *promote = NULL;
        struct in_ifaddr *ifa, *ifa1 = *ifap;
        struct in_ifaddr *last_prim = in_dev->ifa_list;
        struct in_ifaddr *prev_prom = NULL;
        int do_promote = IN_DEV_PROMOTE_SECONDARIES(in_dev);

        ASSERT_RTNL();

        /* 1. Deleting primary ifaddr forces deletion all secondaries
         * unless alias promotion is set
         **/

        if (!(ifa1->ifa_flags & IFA_F_SECONDARY)) {
                struct in_ifaddr **ifap1 = &ifa1->ifa_next;

                while ((ifa = *ifap1) != NULL) {
                        if (!(ifa->ifa_flags & IFA_F_SECONDARY) &&
                            ifa1->ifa_scope <= ifa->ifa_scope)
                                last_prim = ifa;

                        if (!(ifa->ifa_flags & IFA_F_SECONDARY) ||
                            ifa1->ifa_mask != ifa->ifa_mask ||
                            !inet_ifa_match(ifa1->ifa_address, ifa)) {
                                ifap1 = &ifa->ifa_next;
                                prev_prom = ifa;
                                continue;
                        }

                        if (!do_promote) {
                                *ifap1 = ifa->ifa_next;

                                rtmsg_ifa(RTM_DELADDR, ifa, nlh, pid);
                                blocking_notifier_call_chain(&inetaddr_chain,
                                                NETDEV_DOWN, ifa);
                                inet_free_ifa(ifa);
                        } else {
                                promote = ifa;
                                break;
                        }
                }
        }

        /* 2. Unlink it */

        *ifap = ifa1->ifa_next;

        /* 3. Announce address deletion */

        /* Send message first, then call notifier.
           At first sight, FIB update triggered by notifier
           will refer to already deleted ifaddr, that could confuse
           netlink listeners. It is not true: look, gated sees
           that route deleted and if it still thinks that ifaddr
           is valid, it will try to restore deleted routes... Grr.
           So that, this order is correct.
         */
        rtmsg_ifa(RTM_DELADDR, ifa1, nlh, pid);
        blocking_notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa1);

        if (promote) {

                if (prev_prom) {
                        prev_prom->ifa_next = promote->ifa_next;
                        promote->ifa_next = last_prim->ifa_next;
                        last_prim->ifa_next = promote;
                }

                promote->ifa_flags &= ~IFA_F_SECONDARY;
                rtmsg_ifa(RTM_NEWADDR, promote, nlh, pid);
                blocking_notifier_call_chain(&inetaddr_chain,
                                NETDEV_UP, promote);
                for (ifa = promote->ifa_next; ifa; ifa = ifa->ifa_next) {
                        if (ifa1->ifa_mask != ifa->ifa_mask ||
                            !inet_ifa_match(ifa1->ifa_address, ifa))
                                        continue;
                        fib_add_ifaddr(ifa);
                }

        }
        if (destroy)
                inet_free_ifa(ifa1);
}

static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                         int destroy)
{
        __inet_del_ifa(in_dev, ifap, destroy, NULL, 0);
}

static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
                             u32 pid)
{
        struct in_device *in_dev = ifa->ifa_dev;
        struct in_ifaddr *ifa1, **ifap, **last_primary;

        ASSERT_RTNL();

        if (!ifa->ifa_local) {
                inet_free_ifa(ifa);
                return 0;
        }

        ifa->ifa_flags &= ~IFA_F_SECONDARY;
        last_primary = &in_dev->ifa_list;

        for (ifap = &in_dev->ifa_list; (ifa1 = *ifap) != NULL;
             ifap = &ifa1->ifa_next) {
                if (!(ifa1->ifa_flags & IFA_F_SECONDARY) &&
                    ifa->ifa_scope <= ifa1->ifa_scope)
                        last_primary = &ifa1->ifa_next;
                if (ifa1->ifa_mask == ifa->ifa_mask &&
                    inet_ifa_match(ifa1->ifa_address, ifa)) {
                        if (ifa1->ifa_local == ifa->ifa_local) {
                                inet_free_ifa(ifa);
                                return -EEXIST;
                        }
                        if (ifa1->ifa_scope != ifa->ifa_scope) {
                                inet_free_ifa(ifa);
                                return -EINVAL;
                        }
                        ifa->ifa_flags |= IFA_F_SECONDARY;
                }
        }

        if (!(ifa->ifa_flags & IFA_F_SECONDARY)) {
                net_srandom(ifa->ifa_local);
                ifap = last_primary;
        }

        ifa->ifa_next = *ifap;
        *ifap = ifa;

        /* Send message first, then call notifier.
           Notifier will trigger FIB update, so that
           listeners of netlink will know about new ifaddr */
        rtmsg_ifa(RTM_NEWADDR, ifa, nlh, pid);
        blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);

        return 0;
}

static int inet_insert_ifa(struct in_ifaddr *ifa)
{
        return __inet_insert_ifa(ifa, NULL, 0);
}

static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
{
        struct in_device *in_dev = __in_dev_get_rtnl(dev);

        ASSERT_RTNL();

        if (!in_dev) {
                inet_free_ifa(ifa);
                return -ENOBUFS;
        }
        ipv4_devconf_setall(in_dev);
        if (ifa->ifa_dev != in_dev) {
                WARN_ON(ifa->ifa_dev);
                in_dev_hold(in_dev);
                ifa->ifa_dev = in_dev;
        }
        if (ipv4_is_loopback(ifa->ifa_local))
                ifa->ifa_scope = RT_SCOPE_HOST;
        return inet_insert_ifa(ifa);
}

struct in_device *inetdev_by_index(struct net *net, int ifindex)
{
        struct net_device *dev;
        struct in_device *in_dev = NULL;
        read_lock(&dev_base_lock);
        dev = __dev_get_by_index(net, ifindex);
        if (dev)
                in_dev = in_dev_get(dev);
        read_unlock(&dev_base_lock);
        return in_dev;
}

/* Called only from RTNL semaphored context. No locks. */

struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
                                    __be32 mask)
{
        ASSERT_RTNL();

        for_primary_ifa(in_dev) {
                if (ifa->ifa_mask == mask && inet_ifa_match(prefix, ifa))
                        return ifa;
        } endfor_ifa(in_dev);
        return NULL;
}

static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr *tb[IFA_MAX+1];
        struct in_device *in_dev;
        struct ifaddrmsg *ifm;
        struct in_ifaddr *ifa, **ifap;
        int err = -EINVAL;

        ASSERT_RTNL();

        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
        if (err < 0)
                goto errout;

        ifm = nlmsg_data(nlh);
        in_dev = inetdev_by_index(net, ifm->ifa_index);
        if (in_dev == NULL) {
                err = -ENODEV;
                goto errout;
        }

        __in_dev_put(in_dev);

        for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
             ifap = &ifa->ifa_next) {
                if (tb[IFA_LOCAL] &&
                    ifa->ifa_local != nla_get_be32(tb[IFA_LOCAL]))
                        continue;

                if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
                        continue;

                if (tb[IFA_ADDRESS] &&
                    (ifm->ifa_prefixlen != ifa->ifa_prefixlen ||
                    !inet_ifa_match(nla_get_be32(tb[IFA_ADDRESS]), ifa)))
                        continue;

                __inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).pid);
                return 0;
        }

        err = -EADDRNOTAVAIL;
errout:
        return err;
}

static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh)
{
        struct nlattr *tb[IFA_MAX+1];
        struct in_ifaddr *ifa;
        struct ifaddrmsg *ifm;
        struct net_device *dev;
        struct in_device *in_dev;
        int err;

        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
        if (err < 0)
                goto errout;

        ifm = nlmsg_data(nlh);
        err = -EINVAL;
        if (ifm->ifa_prefixlen > 32 || tb[IFA_LOCAL] == NULL)
                goto errout;

        dev = __dev_get_by_index(net, ifm->ifa_index);
        err = -ENODEV;
        if (dev == NULL)
                goto errout;

        in_dev = __in_dev_get_rtnl(dev);
        err = -ENOBUFS;
        if (in_dev == NULL)
                goto errout;

        ifa = inet_alloc_ifa();
        if (ifa == NULL)
                /*
                 * A potential indev allocation can be left alive, it stays
                 * assigned to its device and is destroy with it.
                 */
                goto errout;

        ipv4_devconf_setall(in_dev);
        in_dev_hold(in_dev);

        if (tb[IFA_ADDRESS] == NULL)
                tb[IFA_ADDRESS] = tb[IFA_LOCAL];

        ifa->ifa_prefixlen = ifm->ifa_prefixlen;
        ifa->ifa_mask = inet_make_mask(ifm->ifa_prefixlen);
        ifa->ifa_flags = ifm->ifa_flags;
        ifa->ifa_scope = ifm->ifa_scope;
        ifa->ifa_dev = in_dev;

        ifa->ifa_local = nla_get_be32(tb[IFA_LOCAL]);
        ifa->ifa_address = nla_get_be32(tb[IFA_ADDRESS]);

        if (tb[IFA_BROADCAST])
                ifa->ifa_broadcast = nla_get_be32(tb[IFA_BROADCAST]);

        if (tb[IFA_LABEL])
                nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
        else
                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);

        return ifa;

errout:
        return ERR_PTR(err);
}

static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        struct in_ifaddr *ifa;

        ASSERT_RTNL();

        ifa = rtm_to_ifaddr(net, nlh);
        if (IS_ERR(ifa))
                return PTR_ERR(ifa);

        return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).pid);
}

/*
 *      Determine a default network mask, based on the IP address.
 */

static __inline__ int inet_abc_len(__be32 addr)
{
        int rc = -1;    /* Something else, probably a multicast. */

        if (ipv4_is_zeronet(addr))
                rc = 0;
        else {
                __u32 haddr = ntohl(addr);

                if (IN_CLASSA(haddr))
                        rc = 8;
                else if (IN_CLASSB(haddr))
                        rc = 16;
                else if (IN_CLASSC(haddr))
                        rc = 24;
        }

        return rc;
}


int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
{
        struct ifreq ifr;
        struct sockaddr_in sin_orig;
        struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
        struct in_device *in_dev;
        struct in_ifaddr **ifap = NULL;
        struct in_ifaddr *ifa = NULL;
        struct net_device *dev;
        char *colon;
        int ret = -EFAULT;
        int tryaddrmatch = 0;

        /*
         *      Fetch the caller's info block into kernel space
         */

        if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
                goto out;
        ifr.ifr_name[IFNAMSIZ - 1] = 0;

        /* save original address for comparison */
        memcpy(&sin_orig, sin, sizeof(*sin));

        colon = strchr(ifr.ifr_name, ':');
        if (colon)
                *colon = 0;

#ifdef CONFIG_KMOD
        dev_load(net, ifr.ifr_name);
#endif

        switch (cmd) {
        case SIOCGIFADDR:       /* Get interface address */
        case SIOCGIFBRDADDR:    /* Get the broadcast address */
        case SIOCGIFDSTADDR:    /* Get the destination address */
        case SIOCGIFNETMASK:    /* Get the netmask for the interface */
                /* Note that these ioctls will not sleep,
                   so that we do not impose a lock.
                   One day we will be forced to put shlock here (I mean SMP)
                 */
                tryaddrmatch = (sin_orig.sin_family == AF_INET);
                memset(sin, 0, sizeof(*sin));
                sin->sin_family = AF_INET;
                break;

        case SIOCSIFFLAGS:
                ret = -EACCES;
                if (!capable(CAP_NET_ADMIN))
                        goto out;
                break;
        case SIOCSIFADDR:       /* Set interface address (and family) */
        case SIOCSIFBRDADDR:    /* Set the broadcast address */
        case SIOCSIFDSTADDR:    /* Set the destination address */
        case SIOCSIFNETMASK:    /* Set the netmask for the interface */
                ret = -EACCES;
                if (!capable(CAP_NET_ADMIN))
                        goto out;
                ret = -EINVAL;
                if (sin->sin_family != AF_INET)
                        goto out;
                break;
        default:
                ret = -EINVAL;
                goto out;
        }

        rtnl_lock();

        ret = -ENODEV;
        if ((dev = __dev_get_by_name(net, ifr.ifr_name)) == NULL)
                goto done;

        if (colon)
                *colon = ':';

        if ((in_dev = __in_dev_get_rtnl(dev)) != NULL) {
                if (tryaddrmatch) {
                        /* Matthias Andree */
                        /* compare label and address (4.4BSD style) */
                        /* note: we only do this for a limited set of ioctls
                           and only if the original address family was AF_INET.
                           This is checked above. */
                        for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
                             ifap = &ifa->ifa_next) {
                                if (!strcmp(ifr.ifr_name, ifa->ifa_label) &&
                                    sin_orig.sin_addr.s_addr ==
                                                        ifa->ifa_address) {
                                        break; /* found */
                                }
                        }
                }
                /* we didn't get a match, maybe the application is
                   4.3BSD-style and passed in junk so we fall back to
                   comparing just the label */
                if (!ifa) {
                        for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
                             ifap = &ifa->ifa_next)
                                if (!strcmp(ifr.ifr_name, ifa->ifa_label))
                                        break;
                }
        }

        ret = -EADDRNOTAVAIL;
        if (!ifa && cmd != SIOCSIFADDR && cmd != SIOCSIFFLAGS)
                goto done;

        switch (cmd) {
        case SIOCGIFADDR:       /* Get interface address */
                sin->sin_addr.s_addr = ifa->ifa_local;
                goto rarok;

        case SIOCGIFBRDADDR:    /* Get the broadcast address */
                sin->sin_addr.s_addr = ifa->ifa_broadcast;
                goto rarok;

        case SIOCGIFDSTADDR:    /* Get the destination address */
                sin->sin_addr.s_addr = ifa->ifa_address;
                goto rarok;

        case SIOCGIFNETMASK:    /* Get the netmask for the interface */
                sin->sin_addr.s_addr = ifa->ifa_mask;
                goto rarok;

        case SIOCSIFFLAGS:
                if (colon) {
                        ret = -EADDRNOTAVAIL;
                        if (!ifa)
                                break;
                        ret = 0;
                        if (!(ifr.ifr_flags & IFF_UP))
                                inet_del_ifa(in_dev, ifap, 1);
                        break;
                }
                ret = dev_change_flags(dev, ifr.ifr_flags);
                break;

        case SIOCSIFADDR:       /* Set interface address (and family) */
                ret = -EINVAL;
                if (inet_abc_len(sin->sin_addr.s_addr) < 0)
                        break;

                if (!ifa) {
                        ret = -ENOBUFS;
                        if ((ifa = inet_alloc_ifa()) == NULL)
                                break;
                        if (colon)
                                memcpy(ifa->ifa_label, ifr.ifr_name, IFNAMSIZ);
                        else
                                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                } else {
                        ret = 0;
                        if (ifa->ifa_local == sin->sin_addr.s_addr)
                                break;
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_broadcast = 0;
                        ifa->ifa_scope = 0;
                }

                ifa->ifa_address = ifa->ifa_local = sin->sin_addr.s_addr;

                if (!(dev->flags & IFF_POINTOPOINT)) {
                        ifa->ifa_prefixlen = inet_abc_len(ifa->ifa_address);
                        ifa->ifa_mask = inet_make_mask(ifa->ifa_prefixlen);
                        if ((dev->flags & IFF_BROADCAST) &&
                            ifa->ifa_prefixlen < 31)
                                ifa->ifa_broadcast = ifa->ifa_address |
                                                     ~ifa->ifa_mask;
                } else {
                        ifa->ifa_prefixlen = 32;
                        ifa->ifa_mask = inet_make_mask(32);
                }
                ret = inet_set_ifa(dev, ifa);
                break;

        case SIOCSIFBRDADDR:    /* Set the broadcast address */
                ret = 0;
                if (ifa->ifa_broadcast != sin->sin_addr.s_addr) {
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_broadcast = sin->sin_addr.s_addr;
                        inet_insert_ifa(ifa);
                }
                break;

        case SIOCSIFDSTADDR:    /* Set the destination address */
                ret = 0;
                if (ifa->ifa_address == sin->sin_addr.s_addr)
                        break;
                ret = -EINVAL;
                if (inet_abc_len(sin->sin_addr.s_addr) < 0)
                        break;
                ret = 0;
                inet_del_ifa(in_dev, ifap, 0);
                ifa->ifa_address = sin->sin_addr.s_addr;
                inet_insert_ifa(ifa);
                break;

        case SIOCSIFNETMASK:    /* Set the netmask for the interface */

                /*
                 *      The mask we set must be legal.
                 */
                ret = -EINVAL;
                if (bad_mask(sin->sin_addr.s_addr, 0))
                        break;
                ret = 0;
                if (ifa->ifa_mask != sin->sin_addr.s_addr) {
                        __be32 old_mask = ifa->ifa_mask;
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_mask = sin->sin_addr.s_addr;
                        ifa->ifa_prefixlen = inet_mask_len(ifa->ifa_mask);

                        /* See if current broadcast address matches
                         * with current netmask, then recalculate
                         * the broadcast address. Otherwise it's a
                         * funny address, so don't touch it since
                         * the user seems to know what (s)he's doing...
                         */
                        if ((dev->flags & IFF_BROADCAST) &&
                            (ifa->ifa_prefixlen < 31) &&
                            (ifa->ifa_broadcast ==
                             (ifa->ifa_local|~old_mask))) {
                                ifa->ifa_broadcast = (ifa->ifa_local |
                                                      ~sin->sin_addr.s_addr);
                        }
                        inet_insert_ifa(ifa);
                }
                break;
        }
done:
        rtnl_unlock();
out:
        return ret;
rarok:
        rtnl_unlock();
        ret = copy_to_user(arg, &ifr, sizeof(struct ifreq)) ? -EFAULT : 0;
        goto out;
}

static int inet_gifconf(struct net_device *dev, char __user *buf, int len)
{
        struct in_device *in_dev = __in_dev_get_rtnl(dev);
        struct in_ifaddr *ifa;
        struct ifreq ifr;
        int done = 0;

        if (!in_dev || (ifa = in_dev->ifa_list) == NULL)
                goto out;

        for (; ifa; ifa = ifa->ifa_next) {
                if (!buf) {
                        done += sizeof(ifr);
                        continue;
                }
                if (len < (int) sizeof(ifr))
                        break;
                memset(&ifr, 0, sizeof(struct ifreq));
                if (ifa->ifa_label)
                        strcpy(ifr.ifr_name, ifa->ifa_label);
                else
                        strcpy(ifr.ifr_name, dev->name);

                (*(struct sockaddr_in *)&ifr.ifr_addr).sin_family = AF_INET;
                (*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr =
                                                                ifa->ifa_local;

                if (copy_to_user(buf, &ifr, sizeof(struct ifreq))) {
                        done = -EFAULT;
                        break;
                }
                buf  += sizeof(struct ifreq);
                len  -= sizeof(struct ifreq);
                done += sizeof(struct ifreq);
        }
out:
        return done;
}

__be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
{
        __be32 addr = 0;
        struct in_device *in_dev;
        struct net *net = dev_net(dev);

        rcu_read_lock();
        in_dev = __in_dev_get_rcu(dev);
        if (!in_dev)
                goto no_in_dev;

        for_primary_ifa(in_dev) {
                if (ifa->ifa_scope > scope)
                        continue;
                if (!dst || inet_ifa_match(dst, ifa)) {
                        addr = ifa->ifa_local;
                        break;
                }
                if (!addr)
                        addr = ifa->ifa_local;
        } endfor_ifa(in_dev);
no_in_dev:
        rcu_read_unlock();

        if (addr)
                goto out;

        /* Not loopback addresses on loopback should be preferred
           in this case. It is importnat that lo is the first interface
           in dev_base list.
         */
        read_lock(&dev_base_lock);
        rcu_read_lock();
        for_each_netdev(net, dev) {
                if ((in_dev = __in_dev_get_rcu(dev)) == NULL)
                        continue;

                for_primary_ifa(in_dev) {
                        if (ifa->ifa_scope != RT_SCOPE_LINK &&
                            ifa->ifa_scope <= scope) {
                                addr = ifa->ifa_local;
                                goto out_unlock_both;
                        }
                } endfor_ifa(in_dev);
        }
out_unlock_both:
        read_unlock(&dev_base_lock);
        rcu_read_unlock();
out:
        return addr;
}

static __be32 confirm_addr_indev(struct in_device *in_dev, __be32 dst,
                              __be32 local, int scope)
{
        int same = 0;
        __be32 addr = 0;

        for_ifa(in_dev) {
                if (!addr &&
                    (local == ifa->ifa_local || !local) &&
                    ifa->ifa_scope <= scope) {
                        addr = ifa->ifa_local;
                        if (same)
                                break;
                }
                if (!same) {
                        same = (!local || inet_ifa_match(local, ifa)) &&
                                (!dst || inet_ifa_match(dst, ifa));
                        if (same && addr) {
                                if (local || !dst)
                                        break;
                                /* Is the selected addr into dst subnet? */
                                if (inet_ifa_match(addr, ifa))
                                        break;
                                /* No, then can we use new local src? */
                                if (ifa->ifa_scope <= scope) {
                                        addr = ifa->ifa_local;
                                        break;
                                }
                                /* search for large dst subnet for addr */
                                same = 0;
                        }
                }
        } endfor_ifa(in_dev);

        return same? addr : 0;
}

/*
 * Confirm that local IP address exists using wildcards:
 * - in_dev: only on this interface, 0=any interface
 * - dst: only in the same subnet as dst, 0=any dst
 * - local: address, 0=autoselect the local address
 * - scope: maximum allowed scope value for the local address
 */
__be32 inet_confirm_addr(struct in_device *in_dev,
                         __be32 dst, __be32 local, int scope)
{
        __be32 addr = 0;
        struct net_device *dev;
        struct net *net;

        if (scope != RT_SCOPE_LINK)
                return confirm_addr_indev(in_dev, dst, local, scope);

        net = dev_net(in_dev->dev);
        read_lock(&dev_base_lock);
        rcu_read_lock();
        for_each_netdev(net, dev) {
                if ((in_dev = __in_dev_get_rcu(dev))) {
                        addr = confirm_addr_indev(in_dev, dst, local, scope);
                        if (addr)
                                break;
                }
        }
        rcu_read_unlock();
        read_unlock(&dev_base_lock);

        return addr;
}

/*
 *      Device notifier
 */

int register_inetaddr_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&inetaddr_chain, nb);
}

int unregister_inetaddr_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&inetaddr_chain, nb);
}

/* Rename ifa_labels for a device name change. Make some effort to preserve existing
 * alias numbering and to create unique labels if possible.
*/
static void inetdev_changename(struct net_device *dev, struct in_device *in_dev)
{
        struct in_ifaddr *ifa;
        int named = 0;

        for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
                char old[IFNAMSIZ], *dot;

                memcpy(old, ifa->ifa_label, IFNAMSIZ);
                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                if (named++ == 0)
                        goto skip;
                dot = strchr(old, ':');
                if (dot == NULL) {
                        sprintf(old, ":%d", named);
                        dot = old;
                }
                if (strlen(dot) + strlen(dev->name) < IFNAMSIZ) {
                        strcat(ifa->ifa_label, dot);
                } else {
                        strcpy(ifa->ifa_label + (IFNAMSIZ - strlen(dot) - 1), dot);
                }
skip:
                rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
        }
}

static inline bool inetdev_valid_mtu(unsigned mtu)
{
        return mtu >= 68;
}

/* Called only under RTNL semaphore */

static int inetdev_event(struct notifier_block *this, unsigned long event,
                         void *ptr)
{
        struct net_device *dev = ptr;
        struct in_device *in_dev = __in_dev_get_rtnl(dev);

        ASSERT_RTNL();

        if (!in_dev) {
                if (event == NETDEV_REGISTER) {
                        in_dev = inetdev_init(dev);
                        if (!in_dev)
                                return notifier_from_errno(-ENOMEM);
                        if (dev->flags & IFF_LOOPBACK) {
                                IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
                                IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
                        }
                } else if (event == NETDEV_CHANGEMTU) {
                        /* Re-enabling IP */
                        if (inetdev_valid_mtu(dev->mtu))
                                in_dev = inetdev_init(dev);
                }
                goto out;
        }

        switch (event) {
        case NETDEV_REGISTER:
                printk(KERN_DEBUG "inetdev_event: bug\n");
                dev->ip_ptr = NULL;
                break;
        case NETDEV_UP:
                if (!inetdev_valid_mtu(dev->mtu))
                        break;
                if (dev->flags & IFF_LOOPBACK) {
                        struct in_ifaddr *ifa;
                        if ((ifa = inet_alloc_ifa()) != NULL) {
                                ifa->ifa_local =
                                  ifa->ifa_address = htonl(INADDR_LOOPBACK);
                                ifa->ifa_prefixlen = 8;
                                ifa->ifa_mask = inet_make_mask(8);
                                in_dev_hold(in_dev);
                                ifa->ifa_dev = in_dev;
                                ifa->ifa_scope = RT_SCOPE_HOST;
                                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                                inet_insert_ifa(ifa);
                        }
                }
                ip_mc_up(in_dev);
                break;
        case NETDEV_DOWN:
                ip_mc_down(in_dev);
                break;
        case NETDEV_CHANGEMTU:
                if (inetdev_valid_mtu(dev->mtu))
                        break;
                /* disable IP when MTU is not enough */
        case NETDEV_UNREGISTER:
                inetdev_destroy(in_dev);
                break;
        case NETDEV_CHANGENAME:
                /* Do not notify about label change, this event is
                 * not interesting to applications using netlink.
                 */
                inetdev_changename(dev, in_dev);

                devinet_sysctl_unregister(in_dev);
                devinet_sysctl_register(in_dev);
                break;
        }
out:
        return NOTIFY_DONE;
}

static struct notifier_block ip_netdev_notifier = {
        .notifier_call =inetdev_event,
};

static inline size_t inet_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
               + nla_total_size(4) /* IFA_ADDRESS */
               + nla_total_size(4) /* IFA_LOCAL */
               + nla_total_size(4) /* IFA_BROADCAST */
               + nla_total_size(IFNAMSIZ); /* IFA_LABEL */
}

static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
                            u32 pid, u32 seq, int event, unsigned int flags)
{
        struct ifaddrmsg *ifm;
        struct nlmsghdr  *nlh;

        nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        ifm = nlmsg_data(nlh);
        ifm->ifa_family = AF_INET;
        ifm->ifa_prefixlen = ifa->ifa_prefixlen;
        ifm->ifa_flags = ifa->ifa_flags|IFA_F_PERMANENT;
        ifm->ifa_scope = ifa->ifa_scope;
        ifm->ifa_index = ifa->ifa_dev->dev->ifindex;

        if (ifa->ifa_address)
                NLA_PUT_BE32(skb, IFA_ADDRESS, ifa->ifa_address);

        if (ifa->ifa_local)
                NLA_PUT_BE32(skb, IFA_LOCAL, ifa->ifa_local);

        if (ifa->ifa_broadcast)
                NLA_PUT_BE32(skb, IFA_BROADCAST, ifa->ifa_broadcast);

        if (ifa->ifa_label[0])
                NLA_PUT_STRING(skb, IFA_LABEL, ifa->ifa_label);

        return nlmsg_end(skb, nlh);

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        int idx, ip_idx;
        struct net_device *dev;
        struct in_device *in_dev;
        struct in_ifaddr *ifa;
        int s_ip_idx, s_idx = cb->args[0];

        s_ip_idx = ip_idx = cb->args[1];
        idx = 0;
        for_each_netdev(net, dev) {
                if (idx < s_idx)
                        goto cont;
                if (idx > s_idx)
                        s_ip_idx = 0;
                if ((in_dev = __in_dev_get_rtnl(dev)) == NULL)
                        goto cont;

                for (ifa = in_dev->ifa_list, ip_idx = 0; ifa;
                     ifa = ifa->ifa_next, ip_idx++) {
                        if (ip_idx < s_ip_idx)
                                continue;
                        if (inet_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).pid,
                                             cb->nlh->nlmsg_seq,
                                             RTM_NEWADDR, NLM_F_MULTI) <= 0)
                                goto done;
                }
cont:
                idx++;
        }

done:
        cb->args[0] = idx;
        cb->args[1] = ip_idx;

        return skb->len;
}

static void rtmsg_ifa(int event, struct in_ifaddr* ifa, struct nlmsghdr *nlh,
                      u32 pid)
{
        struct sk_buff *skb;
        u32 seq = nlh ? nlh->nlmsg_seq : 0;
        int err = -ENOBUFS;
        struct net *net;

        net = dev_net(ifa->ifa_dev->dev);
        skb = nlmsg_new(inet_nlmsg_size(), GFP_KERNEL);
        if (skb == NULL)
                goto errout;

        err = inet_fill_ifaddr(skb, ifa, pid, seq, event, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_notify(skb, net, pid, RTNLGRP_IPV4_IFADDR, nlh, GFP_KERNEL);
errout:
        if (err < 0)
                rtnl_set_sk_err(net, RTNLGRP_IPV4_IFADDR, err);
}

#ifdef CONFIG_SYSCTL

static void devinet_copy_dflt_conf(struct net *net, int i)
{
        struct net_device *dev;

        read_lock(&dev_base_lock);
        for_each_netdev(net, dev) {
                struct in_device *in_dev;
                rcu_read_lock();
                in_dev = __in_dev_get_rcu(dev);
                if (in_dev && !test_bit(i, in_dev->cnf.state))
                        in_dev->cnf.data[i] = net->ipv4.devconf_dflt->data[i];
                rcu_read_unlock();
        }
        read_unlock(&dev_base_lock);
}

static void inet_forward_change(struct net *net)
{
        struct net_device *dev;
        int on = IPV4_DEVCONF_ALL(net, FORWARDING);

        IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on;
        IPV4_DEVCONF_DFLT(net, FORWARDING) = on;

        read_lock(&dev_base_lock);
        for_each_netdev(net, dev) {
                struct in_device *in_dev;
                if (on)
                        dev_disable_lro(dev);
                rcu_read_lock();
                in_dev = __in_dev_get_rcu(dev);
                if (in_dev)
                        IN_DEV_CONF_SET(in_dev, FORWARDING, on);
                rcu_read_unlock();
        }
        read_unlock(&dev_base_lock);
}

static int devinet_conf_proc(ctl_table *ctl, int write,
                             struct file* filp, void __user *buffer,
                             size_t *lenp, loff_t *ppos)
{
        int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);

        if (write) {
                struct ipv4_devconf *cnf = ctl->extra1;
                struct net *net = ctl->extra2;
                int i = (int *)ctl->data - cnf->data;

                set_bit(i, cnf->state);

                if (cnf == net->ipv4.devconf_dflt)
                        devinet_copy_dflt_conf(net, i);
        }

        return ret;
}

static int devinet_conf_sysctl(ctl_table *table, int __user *name, int nlen,
                               void __user *oldval, size_t __user *oldlenp,
                               void __user *newval, size_t newlen)
{
        struct ipv4_devconf *cnf;
        struct net *net;
        int *valp = table->data;
        int new;
        int i;

        if (!newval || !newlen)
                return 0;

        if (newlen != sizeof(int))
                return -EINVAL;

        if (get_user(new, (int __user *)newval))
                return -EFAULT;

        if (new == *valp)
                return 0;

        if (oldval && oldlenp) {
                size_t len;

                if (get_user(len, oldlenp))
                        return -EFAULT;

                if (len) {
                        if (len > table->maxlen)
                                len = table->maxlen;
                        if (copy_to_user(oldval, valp, len))
                                return -EFAULT;
                        if (put_user(len, oldlenp))
                                return -EFAULT;
                }
        }

        *valp = new;

        cnf = table->extra1;
        net = table->extra2;
        i = (int *)table->data - cnf->data;

        set_bit(i, cnf->state);

        if (cnf == net->ipv4.devconf_dflt)
                devinet_copy_dflt_conf(net, i);

        return 1;
}

static int devinet_sysctl_forward(ctl_table *ctl, int write,
                                  struct file* filp, void __user *buffer,
                                  size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);

        if (write && *valp != val) {
                struct net *net = ctl->extra2;

                if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
                        rtnl_lock();
                        if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
                                inet_forward_change(net);
                        } else if (*valp) {
                                struct ipv4_devconf *cnf = ctl->extra1;
                                struct in_device *idev =
                                        container_of(cnf, struct in_device, cnf);
                                dev_disable_lro(idev->dev);
                        }
                        rtnl_unlock();
                        rt_cache_flush(net, 0);
                }
        }

        return ret;
}

int ipv4_doint_and_flush(ctl_table *ctl, int write,
                         struct file* filp, void __user *buffer,
                         size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
        struct net *net = ctl->extra2;

        if (write && *valp != val)
                rt_cache_flush(net, 0);

        return ret;
}

int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
                                  void __user *oldval, size_t __user *oldlenp,
                                  void __user *newval, size_t newlen)
{
        int ret = devinet_conf_sysctl(table, name, nlen, oldval, oldlenp,
                                      newval, newlen);
        struct net *net = table->extra2;

        if (ret == 1)
                rt_cache_flush(net, 0);

        return ret;
}


#define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc, sysctl) \
        { \
                .ctl_name       = NET_IPV4_CONF_ ## attr, \
                .procname       = name, \
                .data           = ipv4_devconf.data + \
                                  NET_IPV4_CONF_ ## attr - 1, \
                .maxlen         = sizeof(int), \
                .mode           = mval, \
                .proc_handler   = proc, \
                .strategy       = sysctl, \
                .extra1         = &ipv4_devconf, \
        }

#define DEVINET_SYSCTL_RW_ENTRY(attr, name) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc, \
                             devinet_conf_sysctl)

#define DEVINET_SYSCTL_RO_ENTRY(attr, name) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc, \
                             devinet_conf_sysctl)

#define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc, sysctl) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc, sysctl)

#define DEVINET_SYSCTL_FLUSHING_ENTRY(attr, name) \
        DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush, \
                                     ipv4_doint_and_flush_strategy)

static struct devinet_sysctl_table {
        struct ctl_table_header *sysctl_header;
        struct ctl_table devinet_vars[__NET_IPV4_CONF_MAX];
        char *dev_name;
} devinet_sysctl = {
        .devinet_vars = {
                DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
                                             devinet_sysctl_forward,
                                             devinet_conf_sysctl),
                DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),

                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(SHARED_MEDIA, "shared_media"),
                DEVINET_SYSCTL_RW_ENTRY(RP_FILTER, "rp_filter"),
                DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
                                        "accept_source_route"),
                DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
                DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
                DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
                DEVINET_SYSCTL_RW_ENTRY(LOG_MARTIANS, "log_martians"),
                DEVINET_SYSCTL_RW_ENTRY(TAG, "tag"),
                DEVINET_SYSCTL_RW_ENTRY(ARPFILTER, "arp_filter"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),

                DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(FORCE_IGMP_VERSION,
                                              "force_igmp_version"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES,
                                              "promote_secondaries"),
        },
};

static int __devinet_sysctl_register(struct net *net, char *dev_name,
                int ctl_name, struct ipv4_devconf *p)
{
        int i;
        struct devinet_sysctl_table *t;

#define DEVINET_CTL_PATH_DEV    3

        struct ctl_path devinet_ctl_path[] = {
                { .procname = "net", .ctl_name = CTL_NET, },
                { .procname = "ipv4", .ctl_name = NET_IPV4, },
                { .procname = "conf", .ctl_name = NET_IPV4_CONF, },
                { /* to be set */ },
                { },
        };

        t = kmemdup(&devinet_sysctl, sizeof(*t), GFP_KERNEL);
        if (!t)
                goto out;

        for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
                t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
                t->devinet_vars[i].extra1 = p;
                t->devinet_vars[i].extra2 = net;
        }

        /*
         * Make a copy of dev_name, because '.procname' is regarded as const
         * by sysctl and we wouldn't want anyone to change it under our feet
         * (see SIOCSIFNAME).
         */
        t->dev_name = kstrdup(dev_name, GFP_KERNEL);
        if (!t->dev_name)
                goto free;

        devinet_ctl_path[DEVINET_CTL_PATH_DEV].procname = t->dev_name;
        devinet_ctl_path[DEVINET_CTL_PATH_DEV].ctl_name = ctl_name;

        t->sysctl_header = register_net_sysctl_table(net, devinet_ctl_path,
                        t->devinet_vars);
        if (!t->sysctl_header)
                goto free_procname;

        p->sysctl = t;
        return 0;

free_procname:
        kfree(t->dev_name);
free:
        kfree(t);
out:
        return -ENOBUFS;
}

static void __devinet_sysctl_unregister(struct ipv4_devconf *cnf)
{
        struct devinet_sysctl_table *t = cnf->sysctl;

        if (t == NULL)
                return;

        cnf->sysctl = NULL;
        unregister_sysctl_table(t->sysctl_header);
        kfree(t->dev_name);
        kfree(t);
}

static void devinet_sysctl_register(struct in_device *idev)
{
        neigh_sysctl_register(idev->dev, idev->arp_parms, NET_IPV4,
                        NET_IPV4_NEIGH, "ipv4", NULL, NULL);
        __devinet_sysctl_register(dev_net(idev->dev), idev->dev->name,
                        idev->dev->ifindex, &idev->cnf);
}

static void devinet_sysctl_unregister(struct in_device *idev)
{
        __devinet_sysctl_unregister(&idev->cnf);
        neigh_sysctl_unregister(idev->arp_parms);
}

static struct ctl_table ctl_forward_entry[] = {
        {
                .ctl_name       = NET_IPV4_FORWARD,
                .procname       = "ip_forward",
                .data           = &ipv4_devconf.data[
                                        NET_IPV4_CONF_FORWARDING - 1],
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = devinet_sysctl_forward,
                .strategy       = devinet_conf_sysctl,
                .extra1         = &ipv4_devconf,
                .extra2         = &init_net,
        },
        { },
};

static __net_initdata struct ctl_path net_ipv4_path[] = {
        { .procname = "net", .ctl_name = CTL_NET, },
        { .procname = "ipv4", .ctl_name = NET_IPV4, },
        { },
};
#endif

static __net_init int devinet_init_net(struct net *net)
{
        int err;
        struct ipv4_devconf *all, *dflt;
#ifdef CONFIG_SYSCTL
        struct ctl_table *tbl = ctl_forward_entry;
        struct ctl_table_header *forw_hdr;
#endif

        err = -ENOMEM;
        all = &ipv4_devconf;
        dflt = &ipv4_devconf_dflt;

        if (net != &init_net) {
                all = kmemdup(all, sizeof(ipv4_devconf), GFP_KERNEL);
                if (all == NULL)
                        goto err_alloc_all;

                dflt = kmemdup(dflt, sizeof(ipv4_devconf_dflt), GFP_KERNEL);
                if (dflt == NULL)
                        goto err_alloc_dflt;

#ifdef CONFIG_SYSCTL
                tbl = kmemdup(tbl, sizeof(ctl_forward_entry), GFP_KERNEL);
                if (tbl == NULL)
                        goto err_alloc_ctl;

                tbl[0].data = &all->data[NET_IPV4_CONF_FORWARDING - 1];
                tbl[0].extra1 = all;
                tbl[0].extra2 = net;
#endif
        }

#ifdef CONFIG_SYSCTL
        err = __devinet_sysctl_register(net, "all",
                        NET_PROTO_CONF_ALL, all);
        if (err < 0)
                goto err_reg_all;

        err = __devinet_sysctl_register(net, "default",
                        NET_PROTO_CONF_DEFAULT, dflt);
        if (err < 0)
                goto err_reg_dflt;

        err = -ENOMEM;
        forw_hdr = register_net_sysctl_table(net, net_ipv4_path, tbl);
        if (forw_hdr == NULL)
                goto err_reg_ctl;
        net->ipv4.forw_hdr = forw_hdr;
#endif

        net->ipv4.devconf_all = all;
        net->ipv4.devconf_dflt = dflt;
        return 0;

#ifdef CONFIG_SYSCTL
err_reg_ctl:
        __devinet_sysctl_unregister(dflt);
err_reg_dflt:
        __devinet_sysctl_unregister(all);
err_reg_all:
        if (tbl != ctl_forward_entry)
                kfree(tbl);
err_alloc_ctl:
#endif
        if (dflt != &ipv4_devconf_dflt)
                kfree(dflt);
err_alloc_dflt:
        if (all != &ipv4_devconf)
                kfree(all);
err_alloc_all:
        return err;
}

static __net_exit void devinet_exit_net(struct net *net)
{
#ifdef CONFIG_SYSCTL
        struct ctl_table *tbl;

        tbl = net->ipv4.forw_hdr->ctl_table_arg;
        unregister_net_sysctl_table(net->ipv4.forw_hdr);
        __devinet_sysctl_unregister(net->ipv4.devconf_dflt);
        __devinet_sysctl_unregister(net->ipv4.devconf_all);
        kfree(tbl);
#endif
        kfree(net->ipv4.devconf_dflt);
        kfree(net->ipv4.devconf_all);
}

static __net_initdata struct pernet_operations devinet_ops = {
        .init = devinet_init_net,
        .exit = devinet_exit_net,
};

void __init devinet_init(void)
{
        register_pernet_subsys(&devinet_ops);

        register_gifconf(PF_INET, inet_gifconf);
        register_netdevice_notifier(&ip_netdev_notifier);

        rtnl_register(PF_INET, RTM_NEWADDR, inet_rtm_newaddr, NULL);
        rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL);
        rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr);
}

EXPORT_SYMBOL(in_dev_finish_destroy);
EXPORT_SYMBOL(inet_select_addr);
EXPORT_SYMBOL(inetdev_by_index);
EXPORT_SYMBOL(register_inetaddr_notifier);
EXPORT_SYMBOL(unregister_inetaddr_notifier);

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